Spabk plug



March 14,1939.

E. B. NOWQSIELSKI SPARK PLUG Filed F eb. 5, 1936 INVENT fdward B. A/owos/e/s/v' 7 BY 7f I Ill/ Patented Mar. 14,1939

PATENT :orrlcs 2,150,123 seam: PLUG Edward B. Nowosielski, Bloomfield, N. 1., assignor to Eclipse Aviation Corporation, ,East .Orange, N. 1., a corporation oi New Jerse:'

Application February 5, 19226, Serial No. 62,524

This invention relates to spark plugs, and par:

either too much or too little heat at any of the points along the path of current flow.

An object of the invention is to provide a spark plug of the type described wherein the sparking. point may be kept within a suitable temperature range and excessive heat rapidly dissipated In this connection a feature of the invention is the provision 01' air circulating means in two distinct regions in the plug assembly, one of which regions of air circulation operates to supplementthe other and. in conjunction therewith, achieve the stated objective.

Another object of the invention is to provide an improved method of shielding and insulating the high tension circuit of a spark plug, as well as a novel structural combination of parts adapted to cooperate in the attainment of improved shielding and insulating properties. For example, I provide, for application to a shielding element'oi the mica sleeve lined type, an improved method or protecting the mica lining, as well asa novel construction of adjacent parts to eliminate the possibility of fraying at the edges 0! the mica, notwithstanding repeated withdrawals and re-insertions of the connecting cable.

The improved insulating properties are due,

in large measure, to the choice of insulating materials oi diiierent composition for use in the dliierent regions of the plug assembly where diii'erent conditions are encountered; and in this respect the" construction diflers radically from that of the all-mica or all-porceiain'plugs oi the prior art. to Inthe embodiment shown I use. three dlflerent materials to answer the diflerent' requirements from the diflerent conditions to be met. I

The three materials chosen, by way of example, are'mica, Bakelite and porcelain-mica as the material to line the radiating tube portion oi the outer shield, Bakelite as the material to protect both the mica lining andthe rubbercovered ignition cable, and porcelainas a material which is superior to stacked micaastheinstrumentality to withstand the persistent flash-over tendencies existing along the surfaces of the center electrode spindle and lower shell. I

These and other objects will appear more fully in the detailed description of the invention which follows. Although only oneembodimentof the present invention is illustrated in the accompanying drawing, it is to be expressly understood that this drawing is for thepurpose of illustration only and is not to beconstrued as a limitation 5 of the scope of the invention, referencebeing had for this purpose to the appended claims.

In the drawing: Fig. 1 is 'a longitudinal sectional view of a device embodying thelnvention; and 1 Fig. 21s a transverse end, or bottom plan view. Referring first to Fig. 1, the apertured shielding element Iii is shown as an upward extension of the cylinder engaging base or shell Ii, there being an intermediate polygonal portion I! which 15 receives a wrench or other tool for insertion of the plug in the cylinder wall. 'l'helower portion of the element ill is also shown as provided with a polygonal section i3 facilitatingits attachment to the shell il,'but it is to be understood that the 20 two members ill and H may be integral if preferred.

In thespace within the element Ill, there is a cooling and ventilating chamber surrounding a long thin'metallic jacket I5 lined with a tube 25 it of rolled mica constituting the wall of a second annular chamber closed at its upper end -.by anon-conducting spacer tube I! having a 14 having an enlarged lower part 39 against which the upperend of coil spring 36 engages to urge the chisel edged upper end of the pin into penetrating engagement with the stranded wire cable-core 4|. V

As shown, the insulated cable 83 is adapted to pass' through-a metal thimble or elbow 31, the latter having a flanged ring 88 soldered to its lower end and pivotable within. the detach- 5 ablecoupling member. 52 threaded on the end of the shielding element in. Before attaching the thimble 31 the spacer tube ll of Bakelite. or other rigid insulating construction is inserted to fit about electrode connection 34, with its skirt 50 telescoping with washer 28. The upper end of the tube I1 is flanged, as at 44, to rest upon asbestos disc and overlie the upper edges of mica lining I6, and thus protect the mica lining After. passing the cable through the elbow thimble 31, a metal bracelet or collar 43 is pressed a tightly about the rubber coating of the cable, at a P int which is a pre-measured distance fromthe end'of the cable. Coupling nut 52 and thimble 38, the latter being recessed to form an annular ledge ii are then moved forward into the assembled relationshipshown, wherein thimble 38 serves as a thrust bearing to prevent withdrawal of the cable so long as coupling member 52 re-- mains in place'as shown. When the member i2 is unscrewed from the shielding element I0 and drawn back (together with thimble 31, 38) alongthe cable, the latter may then be withdrawn. and

i pected, but spacer tube II will remain in place due to the fact that the spun-over end I of element I0 holds upper metallic washer l1 and flange 44 against displacement. Preferably spacer'tube I1 is grooved circum ferentially, as indicated at 62, to facilitate heat dissipation and also to provide space for retention of a binding cement, if it is desired to apply such an auxiliary holding substance.

The-insulator 20 of suitable ceramic material, such as porcelain, is positioned solidly within the shell by the action of threading parts In and II together. This action holds the insulator 20 against the shouldered portion 30 of the shell, a seal against escape or entry of fiuid being eifected sleeve 35 of copper or other material having good heat conducting qualities, whereby a substantial amount of heat may be taken from the electrode I and spindle l4 and transferred through the insulator, to be dissipated along the surfaces of the grooves and through outlets 34. Heat not dissi- Dated in this fashion maybe transferred to the second region of air circulation around the heat radiating Jacket l5, the heat flow path including Darts i9, 28, I8 and I8.

Thus the spindle extension l9 which is riveted to the spindle, serves a double purpose: first, it keeps the spring 36 in place, and secondly, it tends to transfer a large measure of excess heat to the copper ferrule 28, for ultimate radiation by way of jacket l5.

In assembling the plug elements the first step is to braze or otherwise permanently weld the electrode spindle l4 within the metallic sleeve I5, and the second step is to apply a suitable ce-.

ment to the threaded surfaces 38, so that upon threading the spindle carrying sleeve into the porcelain core 20 to the desired distance, the spindle will become securely bonded to the core 20 by virtue of the cement co ed between the registering surfaces of the sleeve 35 and the bore of the core 20. This cementing step, in conjunc- "tion with the gasket ll, renders the plug air and gas tight.

The outer electrode 8 is preferably made as a single piece, electrically or otherwise welded to the shell along the two cylindrical surfaces indicated at 5 and 6, betweenwhich surfaces there is a peripheral groove adapted to vbe filled by metallic ring 4 of a softer material such as copper having greater heat conductivity so as to facilitate the dissipation of excess heat which might other-i tral spindle and exposed at its base to the cylu 7 wise develop into grounded electrode 8. It will also be noted that although the normal path across which the high tension current will jump To conform to standard practice, shell ll willbe made from suitable free-turning steel, while electrode 8 will .be made from bendable metal having good spark resistant qualities, as, for example, a nickel-manganese alloy.

'WhatIcIaimisL 1. In a spark plug of the self-shielding type, the combination with an insulating core of a center electrode carrying spindle secured within said core, a metallic shell surrounding said core and additional metallic means to facilitate heat transfer from said spindle to said shell, a cable receiving spacer tube fitting within the portion of said shell which extends above said core and a metallic skirt secured to said tube, said skirt and spacer tube constituting parts of the plug assembly, and remaining in place independently of the cable which is insertable therewithin.

2. A spark plug 'assembly including a shell, a core of preshaped material. received with n said shell, a central electrode carrying spindle within said core, and a mica lining for said shell, said mica lining being spaced from said core to allow room for circulation of heat convection currents therebetween.

3. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition cable, a central conducting spindle, a I

one-piece insulating core urrounding the central spindle and exposed-a its base to the cylinder gases, and a resilient metal connection between said cable and said, centralconducting spindle, said resllientmetal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core.

.4. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition cable, a central conducting spindle, a one-piece insulating core surrounding the central spindle and exposed at its base to the cylinder gases, and a metal connection between said cable and said central conducting spindle, said metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core.

5. A spark plug assembly comprising, in comb nation with a socketed shell for reception of an ignition cable, a central conducting spindle, a one-piece insulating core surrounding the central spindle and exposed at its base to the cyl inder gases, a. resilient metal connection between said cable and said central conducting spindle, said resilient metal connection having contact with said spindle at a point substantially below I the upper end of said one-piece insulating core,

and a non-metallic spacer tube locked within said shell, to serve as the cable socket.

' 6. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition'cable, a central conducting spindle, a one-piece insulating core surrounding the ceninder gases, a metal connection between said cable and said central conducting spindle, said metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core and a nonmetallic spacer tube locked within said shell, to serve as the cable socket.

'7. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition cable, a central conducting spindle, a

one-piece insulating core surrounding the central spindle and exposed at its base to the cylinder gases, a resilient metal connection between said cable and said central conducting spindle, said resilient metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core, a non-metallic spacer shell, to serve as the cable socket,and a nonmetallic lining for that portion of said shell,

which lies between the base of the cable socket and the upper end of the one-piece insulating core.

8. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition cable, a central conducting spindle, a one-piece insulating core surrounding the central spindle and exposed at' its base to the cylinder gases. 2. metal connection between saidcable and said central conducting spindle, said metal connection having contact with said spindle at a point substantially below the upper end or said one-piece insulating core,

' spacer tube locked within said shell, to serve as the cable socket, and a non-metallic lining for that portion of said shell which lies between the I base of the cable socket and the upper end 0! the one-pieceinsulating core.

9. A spark plug assembly comprising, in combination with a socketed-shell for reception of an ignition cable, a central conducting spindle, a

one-piece insulating core surrounding thecentral spindle and exposed at its baseto the cylinder gases, a resilient metal connection between said cable and said central conducting spindle, said resilient metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core, a non-metallic spacer tube locked within said shell,

to serve as the cable socket. and metallic means tube locked within said a non-metallic cable socket, and metallic means telescopically connecting said insulating core and cable socket.

11. A spark plug assembly comprising, in combination with a socketed shell for reception or an ignition cable, a

central conducting spindle, a one-piece insulating core surrounding the central spindle and exposed atits base to the cylinder gases, a resilient metal connection between said cable and said central conducting spindle, said resilient metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core, anon-metallic spacer tube locked within'said shell, to serve as the cable socket, a non-metallic lining for that portion of said shell which lies between the base of the cable socket and the upper end oi. the one-piece insulating core, and metallic means telescopically connecting said insulatin core and cable socket.

12. A spark plug assembly comprising, in combination with a socketed shell for reception of an ignition cable, a central conducting spindle, a one-piece insulating core surrounding the central spindle and exposed at its base to the cylinder gases, a metal connection between said cable and said central conducting spindle, said metal connection having contact with said spindle at a point substantially below the upper end of said one-piece insulating core, a non-metallic spacer tube locked within said shell, to serve as the cable socket, a non-metallic lining for that portion of said shell which lies between the base of the cable socket an the upper end of the onepiece insulating core. and metallic means telescopically connecting said insulating core and cable socket.

EDWARD B. NOWOSIEIBKI.

the upper end 0! said one-piece insulating core, a non-metallic spacer J tube locked within said shell, to serve as the 

